"Acidity and Alkalinity of Solutions" Common Acids, Alkalis, and Salts PPT Courseware 2

"Acidity and Alkalinity of Solutions" Common Acids, Alkalis, and Salts PPT Courseware 2

Preview of new knowledge

1. Distinguish between acidic solution and alkaline solution

1. Acid-base indicator: A substance that can react with ______ solution or ______ solution to show _____________ is called an acid-base indicator, or indicator for short.

2. Discoloration of commonly used acid-base indicators

2. pH and acidity and alkalinity of solution

To measure the acidity and alkalinity of a solution, _____________ is commonly used, while to measure the pH of a solution, _____________ is commonly used. The acidity and alkalinity of a solution is often expressed as _____.

The relationship between pH and the acidity and alkalinity of the solution is as follows:

(1) When pH____7, the solution is ______.

(2) When pH____7, the solution is ______; the smaller the pH, the more acidic the solution is ____.

(3) When pH____7, the solution is ______; the higher the pH, the more alkaline the solution is ____.

3. Determination of pH

1. The easiest way to measure the pH of a solution is to use _________.

2. Measurement method: Place the pH test paper on a white porcelain plate or glass piece, use a glass rod or a plastic tip dropper to take a small amount of the solution to be tested, drop it on __________, and then compare the color displayed on the test paper with ____________. Read the pH of the solution.

4. Solution pH and life activities

The pH of a solution has a significant impact on life activities.

(1) The physiological activities of the human body can only proceed normally within a certain pH range.

(2) The normal growth environment of crops also requires a certain pH range.

Interactive exploration

Research point 1: The acidity and alkalinity of indicators and solutions

[Scenario Display]When we eat apples, oranges, grapes and other fruits, they all have a sour taste.

[Question Research]Do they contain acid and how to measure it? Is it necessarily an alkaline solution that can make a colorless phenolphthalein solution turn red? Does the colorless phenolphthalein solution not change color must be an acid solution?

[Inductive lifting]Acid-base indicators can roughly determine the acidity and alkalinity of substances. Common acid-base indicators include purple litmus solution and colorless phenolphthalein solution. Acid solution refers to a solution whose solute is acid. It must be acidic and can turn purple litmus red, but cannot change the color of colorless phenolphthalein; but the solutes in acidic solutions are not necessarily all acids. Similarly, an alkaline solution must be alkaline and can turn purple litmus blue and colorless phenolphthalein red; but a solution that is alkaline is not necessarily an alkaline solution, such as sodium carbonate solution.

[Application Example]

Example 1: Which of the following statements about acid-base indicators is correct ()

A． Dilute sulfuric acid can make purple litmus solution appear blue and colorless phenolphthalein solution appear red.

B． By adding purple litmus solution dropwise to a colorless solution, you can determine the acidity and alkalinity of the solution.

C. By adding colorless phenolphthalein solution dropwise to a colorless solution, the acidity and alkalinity of the solution can be determined.

D． Purple litmus solution can turn hydrochloric acid red

[Analysis] B Colorless phenolphthalein turns red when exposed to alkaline solutions. It is colorless in acidic or neutral environments and cannot differentiate between acidic and neutral solutions. Acid can turn purple litmus red, but the acid itself does not change color.

[Method Instructions] Acid and alkali solutions interact with acid-base indicators. It is the indicator that changes color, but the acid and alkali solutions themselves do not change color. Acid solution refers to a solution whose solute is acid. It must be acidic and can turn purple litmus solution red, but cannot change color of colorless phenolphthalein solution; but the solutes in acidic solutions are not necessarily all acids. Similarly, an alkaline solution must be alkaline, which can turn a purple litmus solution blue and a colorless phenolphthalein solution red; but a solution that is alkaline is not necessarily an alkaline solution, such as sodium carbonate solution.

Exploration point 2: Test the acidity and alkalinity of the solution

[Question Research]What is used to express the strength of acidity and alkalinity? How to use pH test paper to measure the pH of a solution?

[Integrated improvement]The degree of acidity and alkalinity of a solution is often expressed by pH. The pH of an acidic solution is <7. The smaller the pH, the stronger the acidity. When pH=0, the acidity is the strongest; the pH of a neutral solution=7; the pH of an alkaline solution is >7. The larger the pH, the stronger the alkalinity. When using pH test paper to measure the pH of a solution, first place the pH test paper on a white porcelain plate or glass piece, use a glass rod to dip (or use a rubber dropper to absorb) a small amount of the liquid to be measured, drop it on the pH test paper, and then mix it with Compare the color with the standard color chart to read the pH of the solution to be tested.

Example 2 Wet the pH test paper with water and measure the pH of a solution. The measured pH of the solution is compared with the actual situation. The result is ()

A． equal

B． Too big

C. Small

D． All three outcomes are possible

[Analysis] D When measuring the pH of a solution with pH test paper, do not wet it with water. If it is moistened with water, it is equivalent to diluting the solution to be tested with water. If the solution to be tested is acidic, the pH will be high; if the solution to be tested is alkaline, the pH will be low; if the solution to be tested is neutral, the pH will not change.

[ Method instructions This leads to inaccurate measurement results (after the pH test paper is wetted, measuring an acidic solution will make the measured value larger, and measuring an alkaline solution will make the measured value smaller); when reading, most pH test paper can only read integer digits.

On-site testing

Knowledge point 1: The relationship between pH and the acidity and alkalinity of the solution

1. The solution of the following substances that can turn purple litmus solution red is ()

A． Sodium chloride solution B. sodium hydroxide solution

C. Dilute sulfuric acid D. alcohol solution

2. Among the following substances, the least basic one is ()

A． Egg white (pH: 7~8)

B． Toothpaste (pH: 8～9)

C. Soap (pH: 10～11)

D． Stove cleaner (pH: 12～13)

3. The pH of some common substances in life is shown in Figure 8-1-1. Among the following four substances, the acidity and alkalinity of the following four substances are different: ()

A． soapy water

B． toothpaste

C. watermelon juice

D． polenta

Knowledge point 2: How to measure pH

4． Use pH test paper to measure the pH of the solution. Which of the following descriptions is correct ()

A． The pH test paper is directly immersed in the liquid to be tested

B． The pH test paper is first moistened with water and then immersed in the liquid to be tested

C. The pH of the solution was measured to be 3.5

D． Dip a glass rod into the liquid to be tested and apply it on the pH test paper, observe

Keywords: common acid, alkali and salt teaching courseware, acid and alkaline teaching courseware of solutions, Guangdong Education Edition ninth grade chemistry PPT courseware download, second volume chemistry slide courseware download, common acid, alkali and salt PPT courseware download, solution Acid and alkaline PPT courseware download, .PPT format;

For more information about the PPT courseware "Acidity and Alkalinity of Common Acid, Alkali and Salt Solutions", please click on the acidity and alkalinity of common acid, alkali and salt ppt solutions ppt tag.

"Acidity and Alkalinity of Solutions" Common Acids, Alkalis, and Salts PPT Courseware 4:

"Acidity and Alkalinity of Solutions" Common Acids, Alkalis, and Salts PPT Courseware 4 Knowledge Review Knowledge Point 1 Distinguish between acidic solutions and alkaline solutions To determine the acidity and alkalinity of a solution, you can use _____________. Like litmus and phenolphthalein, they can react with acid or alkali solutions.

"Acidity and Alkalinity of Solutions" Common Acids, Alkalis, and Salts PPT Courseware 3:

"Acidity and Alkalinity of Solutions" Common Acids, Alkalis, and Salts PPT Courseware 3 Learning Objectives 1. Learn to distinguish acidic solutions from alkaline solutions 2. Be able to use acid-base indicators to qualitatively test the acidity and alkalinity of solutions 3. Be able to use pH Test paper quantitatively measures the pH of a solution 4. Know the common...

"Acidity and Alkalinity of Solutions" Common acids, bases, and salts PPT courseware:

"Acidity and Alkalinity of Solutions" Common Acids, Alkalis, and Salts PPT Courseware Learning Objectives 1. Learn to use two indicators, litmus and phenolphthalein, to test the acidity and alkalinity of solutions. 2. Understand the relationship between the acidity and alkalinity of a solution and the pH of the solution, and be able to use pH test paper to quantitatively measure the pH of the solution. 3..